When a carbon steel or low-alloy steel pipe corrodes from flow-accelerated corrosion (“FAC”), hydrogen produced from the corrosion in the pipe diffuses through the pipe wall and escapes from the outside surface of the pipe. FAC in pipes is a specific type of erosion-corrosion resulting in an increased rate of corrosion of carbon or low-alloy steels due to the dissolution of their normally protective oxide layer into water or a water/steam mixture moving through the pipe. There is a known correlation between the rate at which the hydrogen effuses from a pipe and the rate of pipe wall thinning due to corrosion. Hydrogen is also produced in other corrosion reactions such as those involving sulfides in pipes carrying oil and gas. As with FAC, the hydrogen diffuses through the pipe wall and escapes from the outside surface of the pipe.